We are investigating the thermodynamics and kinetics of the interactions of RNA polymerase (and other proteins and model cationic ligands) with nucleic acids. In particular, we are interested in the origins of specificity of interaction between E. coli RNA polymerase and T7 DNA promoters, and the differences between specific and nonspecific binding of this protein to DNA. In related work, we are investigating the aggregation reactions of RNA polymerase.